CS243 Review Session

Giovanni Campagna

Stanford University

February 26th, 2016

Today’s topic

I The homeworkI Analysis of existing interfaces

The homework

I Posted on the website yesterdayI Due next Thursday (March 3rd)I Task 1: write two appsI Task 2: write an interface and an app

Task 0: setting up ThingEngine

I If you have not already, go do it nowI If it does not work, come to me after the sessionI Go apply for developer account too!

Task 1: write two apps

I Look at the examples that are already in the collectionI Look for the supported interfaces in the dev portalI Look at the ThingTalk documentation in the dev portal

Testing apps

Task 2: write an app and an interface

I Choose what interface you want, and sign up for itI Different groups => different interfaces!

The existing code

I https://github.com/Stanford-IoT-Lab/thingpedia-common-devices

I One folder per thing, with manifests at the top

A simple interface: Body Trace Scale

const Tp = require(’thingpedia’);module.exports = new Tp.DeviceClass({

Name: ’BodyTraceScaleDevice’,Kinds: [’scale’],_init: function(engine, state) {

this.parent(engine, state);this.serial = state.serial;this.username = state.username;this.password = state.password;this.uniqueId = ’com.bodytrace.scale-’ + this.serial;this.name = "BodyTrace Scale " + this.serial;this.description = "This is a BodyTrace Scale "

+ "owned by " + this.username;},

});

Handling Auth

I Option 0: no auth at allI Option 1: username and passwordI Option 2: OAuth

The OAuth model

1. User clicks on button2. Redirect to login page by service provider3. User approves login4. Redirect to our server with auth code5. Server calls service provider to convert auth code into access

token6. Server uses access token to make requests

The OAuth model & you

1. User clicks on button2. Your code sets up the redirect3. Redirect to login page by service provider4. User approves login5. Redirect to our server with auth code6. Your code calls service provider to convert auth code

into access token7. Your code uses access token to make requests

OAuth in Jawbone

UseOAuth2: Tp.Helpers.OAuth2({kind: ’com.jawbone.up’,client_id: ’v3sYocgyPaE’,client_secret: ’...’,scope: [’basic_read’, ’extended_read’, ...],authorize: ’https://jawbone.com/auth/oauth2/auth’,get_access_token: ’https://jawbone.com/auth/oauth2/token’,callback: // callback when OAuth is done

})

Completing Authcallback: function(engine, accessToken, refreshToken) {

var auth = ’Bearer ’ + accessToken;return Tp.Helpers.Http.get(

’https://jawbone.com/nudge/api/v.1.1/users/@me’,{ auth: auth,

accept: ’application/json’ }).then(function(response) {

var parsed = JSON.parse(response);return engine.devices.loadOneDevice({

kind: ’com.jawbone.up’,accessToken: accessToken,refreshToken: refreshToken,userId: parsed.data.xid,userName: parsed.data.first + ’ ’ +

parsed.data.last },true);

});}

More complex forms of Auth

I That was OAuth 2.0, aka "good OAuth"I Twitter uses OAuth 1.0I Singificantly less standardI Solve that by providing custom code in UseOAuth2 hook

Packaging up your device

{"name": "thingengine-device-bodytrace-scale","version": "1.0.0","description": "BodyTrace Scale support in ThingEngine","author": "Stanford IoT lab","main": "device.js","dependencies": {

"q": "~1.4.1"}

}

Testing your device

The submission page

I Thing ID: as described in the homeworkI Thing name and description: as shown in the dev portalI Always check "This interface requires additional JS code"

The manifest

{"auth": { "type": "oauth2" },"types": ["online-account"],"global-name": "google","params": {},"triggers": {},"actions": {}

}

Triggers and actions

module.exports = new Tp.ChannelClass({Name: ’MyChannel’,_init: function(engine, device) {// constructor},_doOpen: function() {// start},_doClose: function() {// stop}

});

The easy part: actions

module.exports = new Tp.ChannelClass({Name: ’TwitterSinkChannel’,Extends: Tp.SimpleAction,_init: function(engine, device) {

this.parent();this._twitter = // make twitter API client

},

_doInvoke: function(status) {console.log(’Posting Twitter status’, status);

this._twitter.postTweet({ status: status }, function(err) {console.log(’Tweeting failed: ’ + err);

}, function() { });}

});

Polling triggers

module.exports = new Tp.ChannelClass({Name: ’RESTPollingChannel’,interval: 3600 * 1000 * 3,_init: function(engine, device) {

this.parent();this.url = ...;

},

_onResponse: function(response) {// handle response

}})

Handling the response

_onResponse: function(response) {return Q.nfcall(xml2js.parseString, response).then(function(result) {

var temp = result.weatherdata[’product’][0].time[0];var time = new Date(temp.$.to);var temperature = temp.location[0]

.temperature[0].$.value;var humidity = temp.location[0]

.humidity[0].$.value;var event = [time, temperature, humidity];

this.emitEvent(event);}.bind(this));

}

Other examples

I BodyTrace .sourceI SportRadar .nfl, .nba_team, .soccer_eu_team

What about Jawbone?

I Jawbone has many very similar endpointsI source.js has the common codeI Each channel instantiates source.js

Better than polling

I Set up persistent HTTP connectionI Handle items as they comeI Example: Twitter .source

Recap: what to look at

I BodyTrace: password auth, stateful polling triggerI Sportradar: stateless polling triggerI Jawbone: simple OAuthI Twitter: complex OAuth, non-polling trigger

What NOT to look at

I Do not look atI Google, Facebook (stubs)I Bluetooth Generic (placeholder)I Heatpad (XMPP & hacky)I Test (mock device)I Weather (broken)I LinkedIn (is a "generic device")

Further help

I Hackathon sessions tomorrow (Saturday) and MondayI 2pm to 5pm in Gates 409I Come and talk to me if you’re attempting extra-creditI Come and talk to me if you want to roll your own ThingPedia